DE2650665B2 - Method and device for determining the elapsed playing time or tape length and / or the remaining time of cassettes or reels of tape-shaped information carriers - Google Patents

Description

a) when the first impulses are obtained from the

Take-up reel
al. elapsed playing time

T ₁ , =

D? - <? ■

4- / ι ■ D ₁ - n,

where n is the speed of the second shaft, n _{a is} the speed of the take-up reel, D _{t is} the diameter of the second shaft, d is the core diameter of the take-up reel and μ is the thickness of the tape-shaped information carrier,

and from here

a 2. the used or remaining tape length or the remaining running time from the total playing time and the determined elapsed playing time (T ₃ )

or
b)

7; =

A- μ D ₁ - η,

IU

20th

25th

35

the remaining running time when the first pulses are obtained from the supply reel

45

where n _{v is} the speed of rotation of the supply reel and d is its core diameter, and from this the other values are analogous to a 2.

2. The method according to claim 1, characterized in that the determination of the values during a short test run at any point on the information carrier (10) at a predetermined speed he follows.

3. Apparatus for performing the method according to claim 1 or 2, characterized in that ω that one of the tape reels (11, 13) associated with the first and one with the tape-shaped information carrier (10) in a non-positive or positive connection with the second shaft (12) Each one per revolution one or more impulses emitting disc are connected, that the separate summation of the pulses serving counters (Zu Zi) are available, that the outputs of the counters are connected to a computer (R) and its outputs are in turn connected to display elements £ 4) .

4. Apparatus according to claim 3, characterized in that the disc is a perforated disk (14, 15) to be scanned photoelectrically.

5. Apparatus according to claim 3, characterized in that the disc is such deals with magnetic markings.

6. Apparatus according to claim 3, characterized in that it is one of permanent magnetic Material of the existing pulley.

7. Device according to one of claims 3 to 6, characterized in that the computer consists of a via a read-only memory (ROM) controlled computer circuit.

8. Device according to one of claims 3 to 6, characterized in that the computer consists of a there is a computer circuit controlled by a programmable memory (PROM).

9. Device according to one of claims 3 to 8, characterized in that one of the mechanical, magnetic or electrical scanning of certain characteristic data necessary for the calculation eier coil or cassette serving additional arrangement is available.

10. Device according to one of claims 3 to 9, characterized in that connections for remote transmission of the pulses or calculation results available.

1!. Device according to one of Claims 3 to

10, characterized in that an additional arrangement is available, which shortly before reaching the through mechanical, magnetic or electrical marking of the reel or cassette specified running time triggers an optical or acoustic warning signal and / or causes a shutdown.

12. Device according to one of claims 3 to

11, characterized in that known per se Additional circuits for storing and displaying the results of the arithmetic operations are available.

The invention relates to a method and a device for determining the elapsed playing time or tape length and / or the remaining time of cassettes or reels of tape-shaped information carriers according to the preamble of claim 1.

It is already known to measure the winding diameter of the take-up reel with the aid of optical or mechanical To determine the scanner and to roughly preset the playing time display accordingly. The precision is, however, quite low here.

From the German Auslegeschrift 24 16 060 a tape stand display is known, the display of the The number of revolutions of both winding plates is derived and the number of revolutions of both Winding plate belt run impulses are generated and evaluated for display, the impulses via a Frequency divider are fed to a counter and the number generated per revolution of the two winding plates the belt travel impulses are dimensioned to be larger by the factor of the frequency divider than they would be without the use of the Frequency divider would be sized. The frequency divider should be designed as an up / down counter, its counting direction from the running direction of the tape

is determined. As can be seen from FIG. 2 of this interpretative document results, although this can be an improvement the linearity of the display can be achieved; however, the accuracy of the display is not satisfactory possible.

The invention is based on the object of displaying the playing time as accurately as possible with little effort to enable.

In order to achieve this object, according to the invention, the features in the characterizing part of claims 1 and 3, respectively suggested measures.

The curvature takes into account the given square Correlation between the speeds of the two shafts and thus provides a very precise result; she In addition, it allows a statement to be made about the respective point by means of a short test run at any point Band stand. The previously necessary start of counting at the beginning of the tape is no longer necessary.

Advantageous further developments of the subjects of claims 1 and 3 result from claims 2 and 4 to 12.

Embodiments of the invention are described below with reference to the drawing figures explained. It shows

F i g. 1 supply reel, transport shaft and take-up reel in simplified form,

F i g. 2 is a block diagram.

A tape-shaped information carrier 10, for example an audio or video tape, is continuously fed to a take-up reel 13 from a supply reel 11 in frictional contact with a drive shaft 12. The thickness of the tape-shaped information carrier 10 is μ, the diameter of the shaft 12 D ₁ , the core diameter of the take-up reel 13c / and the winding diameter of the take-up reel 13 D _a .

The elapsed playing time is then in seconds:

If, in accordance with a present exemplary embodiment, D ₁ = 3.65 mm, for d- 36.5 mm, for n, 312.5 rev / sec and for μ = 0.02 mm, then the above equation is as follows dar:

T ₁ , =

- ^ - ) 13.32

3.65

1332.25
'3.65 "

;, = f- ^ ~) -3.65 - 365.

D ₁₁ - d D ₁₁ + d

elapsed tape length
Belt speed

D ₁ ■ n, ■ .τ

As already mentioned above, the core diameter of the shaft 12, c / the core diameter of the take-up reel 13, D _a the winding diameter of the take-up reel 13, n _a the speed of the take-up reel and μ the thickness of the tape-shaped information carrier 10.

The ratio of the diameters D, / D _a is:

D "

where n is the speed of the capstan.

The equation (I) can be simplified as follows:

4 ■ / '

■ n, ■ η

-'φ-'ή-ατ-τ

d ~

4 · ,, · D ₁ ■ η,

It follows from this that the already elapsed playing time T _a can easily be calculated if the speeds n and n “are known. These speeds, in turn, can easily be determined by counting the pulses coming from the pulse disks of the shaft 12 or the take-up reel 13.

For the sake of completeness, it should be mentioned that the constants of equation (7) are of course device-dependent as well as on the thickness of the band-shaped information carrier 10 used. she will therefore change from case to case.

In order to detect a change in the strip thickness for a given device, it is expedient to work with various constants that take this into account.
To determine the speed ratio of the shaft

So 12 and take-up reel 13 during the measuring time, which can be kept very short, the number of pulses coming from the pulse disks 14, 15 of the shaft 12 and the take-up reel 13 is recorded with suitable counters Z \ and Zi , with simple computers known per se R determines the ratio of the number of pulses, squares this value, multiplies the result by a first constant and then reduces the product by the value of a second constant.

If there are unequal pitches of the pulse disks ~~ '40 ben 14, 15 for shaft 12 and take-up reel 13, a conversion to uniformly speed-proportional pulse numbers must of course be carried out beforehand. A relatively simple computer circuit controlled by a ROM or PROM can be used as the computer R in

Form of an integrated circuit can be used.

Any specific data relating to the reel or cassette (tape thickness, total playing time) can be entered by means of corresponding identifications of a mechanical, magnetic or electrical type (breaking out corresponding Fields, magnetic markings, etc.). If there is a corresponding Additional arrangement for the detection of these identifiers (characteristic values) is provided, without the intervention of the In this way, the operator automatically takes into account, for example, the one used in each case Belt thickness can be done by the computer.

The computer module controls an LED or liquid crystal display A via a driver known per se.

bo If a computer R with multiplex input is used, the numbers and functions are entered using an AND element. 16 commands can be entered into the computer R via a transcoder (decoder 4 to 16). If the computer module is responsible for a key

b5 would be conceived and an internal debouncing line which interferes with continuous command input, the encoding circuit must override when changing commands the inhibit input must be blocked.

The instructions to the computer R directly from the ROM or via the data selectors from the two counters can be entered via a 4-bit data bus.

The data selectors themselves are also controlled from the ROM via a 4-bit control line. Included 2 bits are used to switch the selectors and 2 more bits to control the tri-state outputs of the selectors. If both control lines are set to "Low", a NOR element activates a three that can be controlled with 4 bits State accepting element (4-bit tri-state gate) enabled and the instructions get out of the ROM in the data bus.

The addresses of the ROM are controlled with an 8-bit counter.

If this counter can be preset, the memory locations be divided in the ROM and thus several programs run. This is necessary when for example, several strip thicknesses should be adjustable.

After the - as already mentioned - very short measuring process has elapsed, there is a release memory free both the counter and the ROM so that the program can run.

If the 2-bit bus for the data selectors does not change data, the program is ended. The release memory is reset via a retriggerable monoflop and the counters Z \ and Z-> are set to zero via a second monoflop. The measuring and calculating process is thus ended.

In order for the computer to continue counting at the start and forerun, the data bus must be used for each step pulse + I, for return - 1 must be entered.

Since the computer R required here is an integrated

Circuit can be designed and is therefore cheap, the subject of the invention opens a cheaper one

ι yet reliable way of identifying your elapsed playing time or tape length and / or the remaining time of cassettes or reels in tape form Information carrier.

For the sake of completeness it should be pointed out

U) sen that of course instead of identifying the Speed of the take-up reel 13 and the speed of the supply reel 11 can be determined and then instead of the elapsed playing time or tape length, the remaining playing time or tape length can be determined.

ι j By simultaneously determining the remaining term or -band length can be adjusted with the help of the computer when a certain specified minimum remaining time is reached or tape length, a warning signal and, if necessary, an automatic shutdown can be triggered.

In many cases, however, a measurement of the remaining time is unnecessary and it should be sufficient for the Total running time or tape length by the operator or - as described above - by means of specific characteristics, which are supported by a suitable

2) Additional arrangement mechanical, magnetic or electrical on the cassette or spool can be scanned to enter into the computer.

The measures according to the invention can be applied to both cassettes and reels of entertainment electronics

jo as well as in data processing and on others Areas to be carried out advantageously.

1 sheet of drawings

Claims (1)

Patent claims: 1. Procedure for determining the elapsed playing time or tape length and / or the remaining time of cassettes or reels of tape-shaped information carriers, at least one of which is one Tape winding plate associated with the first shaft detected first impulses that are dependent on the angle of rotation, related to second impulses and then the elapsed playing time and / or the Remaining term is determined, characterized that as a second impulse from one of the tape winding discs independent, with the band-shaped information carrier (10) in a force-fitting or form-fitting connection second Wave originating rotation angle dependent second pulses are detected and from the two Pulse chains through associated arithmetic operations ih a computer unit the elapsed playing time and / or the remaining term is determined according to the following mathematical terms: